Interpolymers of vinyl chloride



United States Patent 3,012,019 INTERPOLYll/HERS OF VINYL CHLORIDE Ih'chard H. Martin, in, Springfield, Mass., assignor to Monsanto Chemical Company, St. Louis, Mo., a corporation of Delaware No Drawing. Filed July 31, 1959, Ser. No. 830,698 8 Claims. (Cl. 26087.5)

The present invention relates to novel vinyl chloride interpolymers and to methods for preparing same.

Vinyl chloride homopolymers are widely employed as a surface coating resin, as a wire insulation resin, and for diverse other purposes. A relatively recent develop ment in the art has been the employment of vinyl chloride polymer insulated Wires as underground electrical cables. The insulation on such underground cables must be able to withstand severe physical punishment and for maximum utility requires vinyl chloride polymers having physical properties superior to those of many of the presently commercially available vinyl chloride homopolymers. In particular, this development requires vinyl chloride polymers having a high tensile strength, a high 100% modulus and a high crush-resistance.

It is known that the physical properties of vinyl cldoride homopolymers such as tensile strength, 100% modulus and crush-resistance can be improved by preparing the polymer under such conditions that higher molecular weights are obtained. To obtain such higher molecular weights it has heretofore been necessary to lower the polymerization temperature or to reduce the concentration of free radical generating polymerization initiator employed or both. Such modifications of the polymerization process increase the cost of preparing vinyl chloride homopolymers in that they lower the rate of polymerization and concomitantly the productive capacity of the equipment in which the polymer is prepared.

A method sometimes proposed for increasing the molecular weight of polymers is to incorporate a small quantity of a cross-linking monomer, i.e., a monomer containing two or more non-conjugated terminal ethylenic groups, in the monomer charge. This method has been used successfully with some polymer systems, but it is not generally applicable to the preparation of vinyl chloride polymers of high molecular weight. In particular, it is difiicult to find cross-linking monomers which will interpolymerize with vinyl chloride at satisfactory rates. Moreover, where interpolymers can be formed, they tend to be quite heterogeneous in composition and in most cases the interpolymer contains a highly gelled fraction which is insoluble in most solvents for the vinyl chloride interpolymer. Such interpolymers, because of their heterogeneity and insoluble gel fraction, can not be employed in surface coating compositions.

It is an object of this invention to provide vinyl chloride polymers having improved physical properties.

Another object of this invention is to provide a process for preparing vinyl chloride polymers of improved physical properties, which process can be carried out in conventional polymerization equipment.

A further object of this invention is to provide a vinyl chloride polymerization process which, with no sacrifice in the rate of polymerization, yields vinyl chloride polymers of improved physical properties.

Other objects and advantages of this invention will be apparent from the following detailed description thereof.

It has been discovered that vinyl chloride polymers of improved physical properties, as compared with vinyl chloride homopolymers prepared under otherwise identical conditions, can be obtained by interpolymerizing minute but critical quantities of a poly-N-allyl substituted aminotriazine with vinyl chloride. Such improved vinyl chloride interpolymers contain 0.0030.30 weight percent of the poly-N-allyl substituted aminotriazine with the balance of the interpolymer being vinyl chloride. The vinyl chloride interpolymers of improved physical properties are obtained at rates of polymerization which are fully equivalent to those obtained in the homopolymerization of vinyl chloride.

As noted earlier herein, it is known that the physical properties of vinyl chloride polymers such as tensile strength, modulus and crush-resistance are improved as the molecular Weight of the vinyl chloride polymer is increased. This is true not only for vinyl chloride polymers per se, but also for formulated vinyl chloride polymer compositions containing plasticizers, pigments, fillers and other conventional polymer compounding ingredients. Since the precision of molecular weight determinations is much higher than the precision of determinations of tensile strength, 100% modulus and crushresistance, the comparison of polymer properties in the subsequent examples is based primarily upon polymer molecular weights, such molecular weights being expressed in terms of the specific viscosities of the polymers. All of the specific viscosities reported herein are determined on 0.4 weight percent solutions of the polymer in cyclohexanone at 25 i005 C. The precision of the reported values is i0.002. The formula employed for calculating specific viscosities is set forth below:

specific y solutlon VISGOSItIYi solvent vlscosity Solvent, viscosity The following examples are set forth to illustrate more clearly the principle and practice of this invention to those skilled in the art. All parts are by weight.

EXAMPLE I Part A A vinyl chloride homopolymer is prepared in a stirred autoclave employing the suspension polymerization system set forth below:

Component: Parts by weight Monomer 100 Water suspending agent 0.15 Lauroyl peroxide 0.25

Equimolar interpolymer of vinyl acetate and maleic anhydride. t

The polymerization is carried out at 51 C. and is completed in about 16 hours. The vinyl chloride homopolymer has a specific viscosity of 0.51.

Part B.

3 contains only 0.02 weight percent of N,N-diallylme1- amine, the specific viscosity of the resulting interpolymer is about 8% higher than the value obtained with the vinyl chloride homopolymer.

Part C The vinyl chloride-N,N-diallylrnelamine interpolymer of Part B is compounded into the wire coating formulation set forth below:

Component: Parts by weight Resin 100 Di(2-ethylhexyl)phthalate 42 Secondary plasticizer 1 22 Clay 20 Calcium carbonate 15 Stabilizer 8 Lubricant l 1 Hydrocarbon type.

The resulting formulation has a tensile Strength of about 2600 psi. and 100% modulus of about 1800 p.s.i. By way of contrast, when the vinyl chloride homopolymer of Example I, Part A is substituted for the vinyl chloridebLN-diallylmelamine interpolymer, the resulting formulation has a tensile strength and 100% modulus approximately 100 points lower.

EXAMPLES IIV Example I, Part B, is repeated except that the N,N- diallylrnelamine contained in the polymerization system is replaced with, respectively, N,N'-diallylmelamine, 2,4- di(methallylamino)-6-chloro-1,3,5-triazine, 2,4 di(allylamino-6-hydroxy-1,3,5-triazine, and 2 diallylamino 4- amino-6-methyl1,3,5 triazine (N,N diallylacetoguan amine). The physical properties of the resulting interpolymers correspond to those of the interpolymer obtained in Example I, Part B.

EXAMPLE VI An interpolymer consisting of 99.97 weight percent of vinyl chloride and 0.03 weight percent of N,N,N"-triallylmelamine is prepared by the procedure of Example I, Part B and has a specific viscosity of about 0.60.

EXAMPLES VII-XI Five vinyl chloride-N,N-diallylmelamine interpolymers containing varying quantities of N,N-diallylmelamine are prepared under identical polymerization conditions following the proceduce of Example I, Part B. The composition of the interpolymers and the specific viscosities thereof are set forth in Table I.

TABLE I Wt. Percent Polymer N ,N-D iallyl- Specific melamine in Viscosity Iuterpolymer Control-Vinyl Chloride Homopoly- 0 51 0.01 0. 53 0. 03 0.56 0.05 0. 60 Example X 0.08 0. 64 Example XI 0. 10 0. 68

polymers consisting of vinyl chloride and a poly-N-allyl substituted aminotriazine, which for the sake of brevity will sometimes be referred to simply as the polyallyl compound. The polyallyl compounds which can be employed in the practice of this invention are characterized by (1) containing a 1,3,5-triazine ring, (2) containing at least one amino group attached to at least one of the 2,4,6 positions of the 1,3,5-triazine ring, (3) having 2 or 3 hydrogen atoms of the amino groups mentioned in (2) replaced with an allyl or a methallyl group, and (4) containing no poiymerizable terminal ethylenic groups other than those specified in (3). The polyallyl compounds may, among others, conform to any of the following struc- Where R and R are independently selected from the group consisting of a hydrogen atom and a methyl radical and R and Rs, are a hydrogen atom or a monovalent radical,

where R and R are independently selected from the group consisting of a hydrogen atom and a methyl radical and R R and R are a hydrogen atom or a monovalent radical, and

where R R and R are independently selected from the group consisting of a hydrogen atom and a methyl radical and R R and R are a hydrogen atom or a monovalent radical. Typical examples of the polyallyl compounds include, among others, 2-dirnethallylamino-4,6- diamino-l,3,5-triazine(N,N dimethallylmelamine), 2,4- di(allylamino)-6-amin0 1,3,5 triazine(N,Ndiallylmelamine), 2,4-di(allylamino)-l,3,5 triazine(N,N' diallylformoguanamine), 2,4-di(allylamino) .6 chloro 1,3,5- triazine, 2-di(allylamino)-4-chloro 6 hydroxy 1,3,5- triazine, and 2,4-di(allylamino)-6-phenoxy-1,3,5-triazine.

The proportions of vinyl chloride and polyallyl compound included in the interpolymers will depend upon the number of allyl (or methallyl) groups included in the polyallyl compound. When the polyallyl compound contains 2 allyl (or methallyl) groups, the interpolymer will consist of 99.70-99.99 and preferably 99.85-99.98 weight percent of vinyl chloride and, correspondingly, 0.30-0.01 and perferably 0.15-0.02 weight percent of the polyallyl compound. When the polyallyl compound contains 3 allyl (or methallyl) groups, the interpolymer will consist of 99.95-99.997 and preferably 99.96-99.995 weight percent of vinyl chloride and, correspondingly, 0.05- 0.003 and preferably 0.040.005 Weight percent of the polyallyl compound.

The polyallyl compounds can be prepared by classical methods that are known in the art and many of these compounds are commercially available. For example, the polyallyl compounds can be prepared by reacting N- allyl substituted biguanides with acylating agents such as acyl halides, esters, or acid anhydrides. Alternatively, the polyallyl compounds can be prepared by reacting N-allyl substituted dicyandiamides with nitriles. Perhaps the most convenient method for preparing the polyallyl compounds is by reacting a cyanuric trihalide and especially cyanuric trichloride with allyl (or methallyl) amines. When cyanuric trichloride is reacted with 2 mols of allyl amine, the resulting compound is a 2,4-di(allylamino)-6- halo-1,3,5-triazine and may be used as such in the practice of the invention. Preferably, however, the remaining halogen atom is removed from the triazine ring by reaction with water or an organic compound containing a reactive hydrogen atom. An organic compound is considered to have a reactive hydrogen atom when it is capable of reacting with methyl magnesium iodide to liberate methane in the classical Zerewitinofif reaction (see Niederl and Niederl, Micromethods of Quantitative Organic Analysis, page 263, John Wiley & Sons, New York city, 1946). The reactive hydrogen atoms which fulfill the above condition are normally activated by being a member of a functional group containing an oxygen atom, e.g., a hydroxyl group, a carboxylic acid group, a sulfoxy group, etc.; a basic nitrogen atom, e.g., an amine group, a hydrazine group, an imine group, an amide group, a sulfonamide group, a guanidine group, a urea group, a thiourea group, etc.; or a sulfur atom, e.g., a mercaptan group, a-thiocarboxylic acid group, hydrogen sulfide, etc. Specific examples of reactive hydrogen compounds which may be reacted with the halogen atom on the 1,3,5-triazine ring include alkanols, phenols, aliphatic acids, aromatic acids, amines or the like.

The interpolymers of the invention are preferably prepared by the well-known suspension polymerization process in which the monomers are dispersed as small droplets in water and polymerized therein. Although a watersoluble interpolymer of vinyl acetate and maleic anhydride has been employed as the suspending agent in the examples herein presented, other known suspending agents such as gelatine, protective colloids, etc. may be employed if desired. The polymerizations are carried out at temperatures in the range of 30-70 C. in the presence of free radical generating polymerization initiators such as lauroyl peroxide, benzoyl peroxide, etc.

The interpolymers of this invention have higher molecular weights and better physical properties than corresponding vinyl chloride homopolymers prepared under identical polymerization conditions. Thus, the process of this invention makes possible the attainment of a superior product at no increase in cost. Alternatively, interpolymers of this invention having equivalent physical proper ties to vinyl chloride homopolymers can be prepared at higher polymerization temperatures. Polymerizing the interpolymers at higher temperatures increases the rate of polymerization and raises the productive capacity of the polymerization vessel in which the reaction is carried out. Thus, the interporymers of this invention make possible the attainment of a higher productive capacity per unit of capital investment. In general, the productive capacity of a polymerization vessel for the interpolymers of this invention is approximately 30% higher than the productive capacity of the same vessel for a vinyl chloride homopolymer, both of said polymers being polymerized under conditions which give identical molecular weights.

The interpolymers of this invention may be used interchangeably with vinyl chloride homopolymers in virtually all industrial applications. The interpolymers are particularly suitable for use in the insulation of electric wire and particularly for electric wire that is to be employed as underground cable.

The above descriptions and particularly the examples are set forth by way of illustration only. Many other variations and modifications thereof will be obvious to those skilled in the art and can be made without depart- 6 ing from the spirit and scope of the invention herein disclosed.

What is claimed is:

1. A resinous interpolymer of a binary mixture of monomers consisting of vinyl chloride and a polyallyl compound that is characterized by (1) containing a 1,3,5- triazine ring, (2) containing at least 1 amino group attached to at least one of the 2,4,6 positions of the 1,3,5- =triazine ring, (3) containing 2-3 polymerizable terminal ethylenic groups of the group consisting of an allyl group, a methallyl group and mixtures thereof, said polymer- -izable terminal ethylenic groups replacing hydrogen atoms of the amino groups of (2), and (4) containing no polymerizable terminal ethylenic groups other than those specified. in (3); said monomer mixture consisting of 9970-9999 weight percent of vinyl chloride and, correspondingly, 0.30-0.01 weight percent of the polyallyl compound when the polyvinyl compound contains 2 polymerizable terminal ethylenic groups; said monomer mixture consisting of 99.95-99.997 weight percent of vinyl chloride and, correspondingly, 0.05-0.003 weight percent of the polyallyl compound when the polyallyl compound contains 3 polymerizable terminal ethylenic groups.

2. A resinous interpolymer of a binary mixture of monomers consisting of vinyl chloride and a polyallyl compound that is characterized by (1) containing a 1,3,5- triazine'ring, (2) containing at least 1 amino group at-l tached to at least one of the 2,4,6 positions of the 1,3,5- :triazine ring, (3) containing 2-3 polymerizable terminal ethylenic groups of the group consisting of an allyl group, a methallyl group and mixtures thereof, said polymerizable terminal ethylenic groups replacing hydrogen atoms of the amino groups of (2), and (4) containing no polymerizable terminal ethylenic groups other than those specified in (3); said monomer mixture consisting of 99.85-99.98 weight percent of vinyl chloride and, correspondingly, 0.15-0.02 weight percent of the polyallyl compound when the polyallyl compound contains 2 polymerizable terminal ethylenic groups; said monomer mix ture consisting of 99.96-99.995 weight percent of vinyl chloride and, correspondingly, 0.04-0.005 weight percent of the polyallyl compound when the polyallyl compound contains 3 polymerizable terminal ethylenic groups.

3. A resinous interpolymer of monomers consisting of 99.85-99.98 weight percent of vinyl chloride and, c0rrespondingly, 0.15-0.02 weight percent of N,N-diallylmelamine.

4. A resinous interpolymer of monomers consisting of 99.85-99.98 weight percent of vinyl chloride and, correspondingly, 0.15-0.02 weight percent of N,N-diallylmelamine.

5. A resinous interpolymer of monomers consisting of 99.95-99.997 weight percent of vinyl chloride and, correspondingly, 0.05-0.003 weight percent of N,N',N"- triallylmelamine.

6. An insulated electric wire comprising an electrical conductor carrying an insulating coating of a resinous interpolymer of a binary mixture of monomers consisting of vinyl chloride and a polyallyl compound that is characterized by (1) containing a 1,3,5-triazine ring, (2) containing at least 1 amino group attached to at least one of the 2,4,6 positions of the 1,3,5-triazine ring, (3) cont-aining 2-3 polymerizable terminal ethylenic groups of the group consisting of an allyl group, a metallyl group and mixtures thereof, said polymerizable terminal ethylenic groups replacing hydrogen atoms of the amino groups of (2), and (4) containing no polymerizable terminal ethylenic groups other than those specified in (3); said monomer mixture consisting of 99.70-99.99 weight percent of vinyl chloride and, correspondingly, 0.30-0.01 weight percent of the polyallyl compound when the polyallyl compound contains 2 polymerizable terminal ethylenic groups; said monomer mixture consisting of 99.95- 99.997 weight percent of vinyl chloride and, correspondingly, 0.05-0.003 weight percent of the polyallyl compound when the polyallyl compound contains 3 polymerizable terminal ethylenic groups.

7. A suspension polymerization process for preparing a resinous interpolymer of a monomer mixture consisting solely of vinyl chloride and a polyallyl compound, which process comprises dispersing the monomers as droplets in an aqueous medium containing therein a suspending agent and polymerizing the monomers at a temperature of 3070 C. in the presence of a free radical generating polymerization initiator; said polyallyl compound being characterized by (1) containing a 1,3,5-triazine ring, (2) containing at least 1 amino group attachedto at least one of the 2,4,6 positions of the 1,3,5-tn'azine ring, (3) containing 2-3 polymerizable terminal ethylenic groups of the group consisting of an allyl group, a methallyl group and mixtures thereof, said polymerizable terminal ethylenic groups replacing hydrogen atoms of the amino groups of (2), and (4) containing no polymerizable terminal ethylenic groups other than those specified in (3); said monomer mixture consisting of 99 70-9999 weight percent of vinyl chloride and, correspondingly, 0.30-0.01 weight percent of the polyallyl compound when the polyallyl compound contains 2 polymerizable terminal ethylenic groups; said monomer mixture consisting of 99.95- 99.997 weight percent of vinyl chloride and, correspondingly, 0.0541003 weight percent of the polyallyl compound when the polyallyl compound contains 3 polymerizable terminal ethylenic groups.

8. A suspension polymerization process for preparing a resinous interpolymer of a monomer mixture consisting solely of vinyl chloride and a polyallyl compound, which process comprises dispersing the monomers as droplets in an aqueous medium containing therein a suspending agent and polymerizing the monomers at a temperature of 30-70 C. in the presence of a free radical generating polymerization initiator; said polyallyl compound being characterized by (1) containing a 1,3,5-triazine ring, (2) containing at least 1 amino group attached to at least one of the 2,4,6 positions or" the 1,3,5-triazine ring, (3) containing 2-3 polymerizable terminal ethylenic groups of the group consisting of an allyl group, a methallyl group and mixtures thereof, said polymerizable terminal ethylenic groups replacing hydrogen atoms of the amino groups of (2), and (4) containing no polymerizable terminal ethylenic groups other than those specified in (3); said monomer mixture consisting of 99.3599.98 weight percent of vinyl chloride and, correspondingly, 0.15-0.02 weight percent of the polyallyl compound when the polyallyl compound contains 2 polymerizable terminal ethylenic groups; said monomer mixture consisting of 99.96-'

99.995 weight percent of vinyl chloride and, correspondingly, 0.04-0.005 weight percent of the polyallyl compound when the polyallyl compound contains 3 polymerizable terminal ethylenic groups.

References Cited in the file of this patent UNITED STATES PATENTS 2,712,004 Thomas June 28, 1955 UNITED STATES. PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,012,019 December 5, 1962 Richard H. Martin Jr;

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below. I

' Column 4, lines 27 to 33 the upper portion of the formula should appear as shown below instead of as in the patent: R v

column 6, line l8 for po1yvinyl" read polyallyl Signed and sealed this 19th day of June 1962.

(SEAL) Attest:

ERNEST w. SWIDER 7 DAVID L. LADD Attesting officer Commissioner of Patents 

1. A RESINOUS INTERPOLYMER OF A BINARY MIXTURE OF MONOMERS CONSISTING OF VINYL CHLORIDE AND A POLYALLYL COMPOUND THAT IS CHARACTERIZED BY (1) CONTAINING A 1,3,5TRIAZINE RING, (2) CONTAINING AT LEAST 1 AMINO GROUP ATTACHED TO AT LEAST ONE OF THE 2,4,6 POSITIONS OF THE 1,3,5TRIAZINE RING, (3) CONTAINING 2-3 POLYMERIZABLE TERMINAL ETHYLENIC GROUPS OF THE GROUP CONSISTING OF AN ALLYL GROUP, A METHYALLYL GROUP AND MIXTURES THEREOF, SAID POLYMERIZABLE TERMINAL ETHYLENIC GROUPS REPLACING HYDROGEN ATOMS OF THE AMINO GROUPS OF (2) AND (4) CONTAINING NO POLYMERIZABLE TERMINAL ETHYLENIC GROUPS OTHER THAN THOSE SPECIFIED IN (3), SAID MONOMER MIXTURE CONSISTING OF 99.70-99.99 WEIGHT PERCENT OF VINYL CHLORIDE AND, CORRESPONDINGLY, 0.30-0.01 WEIGHT PERCENT OF THE POLYALLYL COMPOUND WHEN THE POLYVINYL COMPOUND CONTAINS 2 POLYMERIZABLE TERMINAL ETHYLENIC GROUPS, SAID MONOMER MIXTURE CONSISTING OF 99.95-99.997 WEIGHT PERCENT OF VINYL CHLORIDE AND, CORRESPONDINGLY, 0.05-0.003 WEIGHT PERCENT OF RHE POLYALLYL COMPOUND WHEN THE POLYALLYL COMPOUND CONTAINS 3 POLYMERIZABLE TERMINAL ETHYLENIC GROUPS. 